The family of TV personality Dr. Phil McGraw is in mourning after his sister-in-law died—20 years after she suffered an acid attack.

People magazine reported this week that Cindi Broaddus, his in-law, died at the age of 68 on Monday, Feb. 19. And an obituary in Oklahoma’s The Duncan Banner said a funeral service was held Feb. 23 on her birthday.

McGraw’s wife, Robin, posted on Instagram this week, saying her sister had died.

“I will celebrate her and her strength and her unwavering support for me the rest of my life. I miss her dearly,” the Instagram caption reads. “I am so proud of you and Angela and Shelli. We are all heartbroken and will miss her everyday. She was our hero. You 3 all made her life a dream. She lived everyday for her daughters and you always made her the happiest woman ever!” she added.

According to Dr. Phil’s website, Broaddus was the victim of a random acid attack when someone threw a jar of sulfuric acid from an overpass. The acid went through the car’s windshield and covered 70 percent of her body.

“I knew I was dying, and I had a very calm peace about me because I had a message that came to me that I had to get through,” she said after the attack. She said that she wanted the driver to tell her kids: “You have got to tell my children how much I love them and that I’m not ready to leave them.”